Light bulb



FIG. 1 is a perspective view of light bulb, as disclosed herein (the hand pictured is for illustration purposes only and forms no part of the claimed invention;

FIG. 2 is a side view thereof;

FIG. 3 is a top view thereof; and,

FIG. 4 is a bottom view thereof. 

The ornamental design for a light bulb, as shown. 